using System;
using System.IO;
using System.Numerics;
using Core;
using Raylib_cs;

namespace Parsons.SteamDeck
{
    class Program
    {
        static void Main(string[] args)
        {
            // 1. Initialize Cross-Platform OpenGL Window
            // THE FIX: Use PascalCase C# enums
            Raylib.SetConfigFlags(ConfigFlags.ResizableWindow);
            Raylib.InitWindow(1280, 800, "Parsons Master System"); // Native Steam Deck Resolution
            Raylib.InitAudioDevice();

            // 2. Initialize Hardware-Agnostic Audio Stream (44.1kHz, 32-bit float, Mono)
            AudioStream audioStream = Raylib.LoadAudioStream(44100, 32, 1);
            Raylib.PlayAudioStream(audioStream);

            // 3. Boot the Core Emulator
            SmsMachine machine = new SmsMachine();
            RaylibAudioPlayer audioPlayer = new RaylibAudioPlayer();
            machine.AudioProcessor.AudioDevice = audioPlayer;

            // Load a ROM (Passed via command line argument, e.g. ./Parsons.SteamDeck sonic.sms)
            if (args.Length > 0 && File.Exists(args[0]))
            {
                machine.LoadCartridge(File.ReadAllBytes(args[0]));
                bool isGG = args[0].EndsWith(".gg", StringComparison.OrdinalIgnoreCase);
                machine.VideoProcessor.IsGameGear = isGG;
            }

            // Lock the engine loop to 60 FPS natively
            Raylib.SetTargetFPS(60);

            // 4. Prepare the Video Texture Pipeline
            // THE FIX: Use Color.Black
            Image img = Raylib.GenImageColor(256, 192, Color.Black);
            Texture2D vdpTexture = Raylib.LoadTextureFromImage(img);
            byte[] pixelBuffer = new byte[256 * 192 * 4]; // Fast RGBA translation array

            // --- THE MAIN GAME LOOP ---
            while (!Raylib.WindowShouldClose())
            {
                // A. OS-Agnostic Input Polling (Works on Keyboard AND Steam Deck Controller)
                // THE FIX: PascalCase KeyboardKey and GamepadButton enums
                byte pad = 0xFF;
                if (Raylib.IsKeyDown(KeyboardKey.Up) || Raylib.IsGamepadButtonDown(0, GamepadButton.LeftFaceUp)) pad &= 0xFE;
                if (Raylib.IsKeyDown(KeyboardKey.Down) || Raylib.IsGamepadButtonDown(0, GamepadButton.LeftFaceDown)) pad &= 0xFD;
                if (Raylib.IsKeyDown(KeyboardKey.Left) || Raylib.IsGamepadButtonDown(0, GamepadButton.LeftFaceLeft)) pad &= 0xFB;
                if (Raylib.IsKeyDown(KeyboardKey.Right) || Raylib.IsGamepadButtonDown(0, GamepadButton.LeftFaceRight)) pad &= 0xF7;

                // Steam Deck "A" Button is RightFaceDown. "B" Button is RightFaceRight.
                if (Raylib.IsKeyDown(KeyboardKey.Z) || Raylib.IsGamepadButtonDown(0, GamepadButton.RightFaceDown)) pad &= 0xEF; // B1 / A Button
                if (Raylib.IsKeyDown(KeyboardKey.X) || Raylib.IsGamepadButtonDown(0, GamepadButton.RightFaceRight)) pad &= 0xDF; // B2 / B Button

                machine.IoBus.Joypad1Keyboard = pad;

                // B. Execute exactly one frame of T-States
                machine.RunFrame();

                // C. Flush Audio Buffer to the Sound Card
                if (Raylib.IsAudioStreamProcessed(audioStream))
                {
                    float[] samples = audioPlayer.GetQueuedSamples();
                    if (samples.Length > 0)
                    {
                        unsafe
                        {
                            fixed (float* p = samples)
                            {
                                Raylib.UpdateAudioStream(audioStream, p, samples.Length);
                            }
                        }
                    }
                }

                // D. Fast Pixel Translation (ARGB int -> RGBA bytes)
                int[] frameBuffer = machine.VideoProcessor.FrameBuffer;
                for (int i = 0; i < frameBuffer.Length; i++)
                {
                    int argb = frameBuffer[i];
                    pixelBuffer[i * 4 + 0] = (byte)((argb >> 16) & 0xFF); // R
                    pixelBuffer[i * 4 + 1] = (byte)((argb >> 8) & 0xFF);  // G
                    pixelBuffer[i * 4 + 2] = (byte)(argb & 0xFF);         // B
                    pixelBuffer[i * 4 + 3] = 255;                         // A
                }

                // Push bytes directly to the GPU Texture
                unsafe
                {
                    fixed (byte* p = pixelBuffer)
                    {
                        Raylib.UpdateTexture(vdpTexture, p);
                    }
                }

                // E. Render to Screen (Perfect Aspect Ratio Scaling)
                Raylib.BeginDrawing();
                Raylib.ClearBackground(Color.Black);

                float scale = Math.Min((float)Raylib.GetScreenWidth() / 256, (float)Raylib.GetScreenHeight() / 192);
                Rectangle sourceRec = new Rectangle(0, 0, 256, 192);
                Rectangle destRec = new Rectangle(
                    (Raylib.GetScreenWidth() - (256 * scale)) * 0.5f,
                    (Raylib.GetScreenHeight() - (192 * scale)) * 0.5f,
                    256 * scale, 192 * scale);

                // Draw the VDP Frame
                Raylib.DrawTexturePro(vdpTexture, sourceRec, destRec, new Vector2(0, 0), 0.0f, Color.White);

                Raylib.EndDrawing();
            }

            // Clean up hardware resources on exit
            Raylib.UnloadTexture(vdpTexture);
            Raylib.UnloadAudioStream(audioStream);
            Raylib.CloseAudioDevice();
            Raylib.CloseWindow();
        }
    }
}